MCR (Maintenance Collateral Ratio) & MSSR (Maximum Short Squeeze Ratio) both normally are static and price feed publisher change it when requested by the asset owner.
Looking that BitCNY MSSR case, why not let the asset owner or committee account have direct control of MCR & MSSR, it will be more efficient for asset owner to test what is the best number MCR & MSSR that are right for their assets.
(Edited by @abitmore)
A draft is here: #218.